Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Lighting Up Semiconductor World… APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 3D Thin Film Transistor Simulation © Crosslight Software, Inc., Vancouver, BC, Canada, (604)320-1704, www.crosslight.com Contents 1. Introduction 2. Process simulation 3. Physical models and parameters 4. Results © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 1. Introduction Amorphous silicon thin film transistors (a-Si:H TFTs) have been widely used in the active-matrix flat panel display due to the low process temperature, uniform device characteristics over large area and low fabrication cost . 3D simuation of TFT is carried out by Maskeditor, CSUPREM and APSYS. MaskEditor is used to generate mask layers. Commands for use by subsequent tools may be added to each layer to generate the device structure. CSUPREM is used to generate the device structure based on the commands defined by MaskEditor. Process simulation may also be performed without using MaskEditor. APSYS is used to simulate the electrical and optical properties of the TFT device. Stand-alone device simulation may also be performed. © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 2. Process simulation TFT mask patterns defined in MaskEditor: •Red mask is used to etch the gate. •Brown mask defines the active part. •Blue mask used to generate the contact. © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 2. Process simulation Process Flow next page In order to view structure clearly, the SiO 2 thickness is limited to 0.1 μm. Aluminum is then deposited with a thickness of 0.18 μm and the red mask is then used to generate the gate. The next step is to deposit 0.35μm of SiN and 0.13μm of intrinsic a-si. The brown mask is then used to generate the active area. © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 2. Process simulation Deposition of 0.15μm a-si with a resistivity of 30Ω*cm. Generation of the contact with the blue mask. ©©2010 2010Crosslight CrosslightSoftware, Software,Inc., Inc.,Burnaby, Burnaby,BC, BC,Canada Canada www.crosslight.com www.crosslight.com APSYS APSYS| CSUPREM | CSUPREM| LASTIP | LASTIP| PICS3D | PICS3D| PROCOM | PROCOM| CROSSLIGHTVIEW | CROSSLIGHTVIEW 2. Process simulation Mesh and doping profile of the device ©©2010 2010Crosslight CrosslightSoftware, Software,Inc., Inc.,Burnaby, Burnaby,BC, BC,Canada Canada www.crosslight.com www.crosslight.com APSYS APSYS| CSUPREM | CSUPREM| LASTIP | LASTIP| PICS3D | PICS3D| PROCOM | PROCOM| CROSSLIGHTVIEW | CROSSLIGHTVIEW 2. Process simulation 2D cut of structure and doping profile at z=40μm. © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 3. Physical models and parameters Doping-dependent carrier mobilities in simulation are defined by: electron_mass value=0.76*me hole_mass value=2.52*me max_electron_mob(μ2n) value=20.e-4 m2/(V*s) min_electron_mob (μ1n) value=1.e-4 m2/(V*s) max_hole_mob (μ2p) value=5.e-4 m2/(V*s) min_hole_mob (μ1p) value=1.e-4 m2/(V*s) ©©2010 2010Crosslight CrosslightSoftware, Software,Inc., Inc.,Burnaby, Burnaby,BC, BC,Canada Canada www.crosslight.com www.crosslight.com APSYS APSYS| CSUPREM | CSUPREM| LASTIP | LASTIP| PICS3D | PICS3D| PROCOM | PROCOM| CROSSLIGHTVIEW | CROSSLIGHTVIEW 3. Physical models and parameters Trap settings are essential for modeling of a-Si devices. Four kinds of traps are used here: trap_conc_2 value=1.e23 /m3 traplevel_tail_2 value=0.05 eV trap_ncap_2 value=2.e-21 m2 trap_pcap_2 value=5.e-20 m2 trap_conc_4 value=1.e22 /m3 traplevel_stddev_4 value=0.1 eV trap_ncap_4 value=2.e-21 m2 trap_pcap_4 value=5.e-20 m2 trap_conc_3 value=1.e23 /m3 traplevel_tail_3 value=0.05 eV trap_ncap_3 value=5.e-20 m2 trap_pcap_3 value=2.e-21 m2 trap_conc_5 value=1.e22 /m3 traplevel_stddev_5 value=0.1 eV trap_ncap_5 value=5.e-20 m2 trap_pcap_5 value=2.e-21 m2 © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 3. Physical models and parameters Trap Models 0.7eV •Traps labeled #2 and #4 are acceptor levels. •Traps labeled #3 and #5 are donor traps. Trap_2: • Due to broadening of the conduction band. Conduction • Energy level has an exponential tail. Trap_4 & Trap_5 : • Due to dangling Si-Si bonds. • Energy level has a Gaussian distribution. 1.78eV 0.88eV Valence Trap_3: • Due to broadening of the valence band. • Energy level has an exponential tail. ©©2010 2010Crosslight CrosslightSoftware, Software,Inc., Inc.,Burnaby, Burnaby,BC, BC,Canada Canada www.crosslight.com www.crosslight.com APSYS APSYS| CSUPREM | CSUPREM| LASTIP | LASTIP| PICS3D | PICS3D| PROCOM | PROCOM| CROSSLIGHTVIEW | CROSSLIGHTVIEW 4. Results Current density distribution @ gate voltage=15 V @ drain voltage=25 V © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 4. Results Potential distribution @ gate voltage=15V @ drain voltage=25V © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 4. Results Threshold voltage Threshold voltage close to 1V Drain Current (A) Drain Current (A) @ Drain voltage=0.5V @ Drain voltage=5V Yellow solid line is automatically generated by software to extract threshold voltage. Gate Voltage (V) Gate Voltage (V) © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW 4. Results Id-Vd family of curves Drain Voltage (V) © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW © 2010 Crosslight Software, Inc., Burnaby, BC, Canada www.crosslight.com APSYS | CSUPREM | LASTIP | PICS3D | PROCOM | CROSSLIGHTVIEW